中文摘要：

采用密度泛函理论B3P86方法研究了AgBr基态分子在不同场强条件下的稳定结构及激发态性质．分析了外电场对AgBr基态分子键长、总能量、能级、谐振频率和红外光谱强度以及对前10个激发态的吸收谱、激发能、振子强度等的影响．结果表明随着正向电场F的逐渐增大，AgBr分子键长逐渐减小；总能量则逐渐升高；分子电偶极矩肛单调减小；HOMO能级升高，而LUMO能级、费米能级和能隙减小．谐振频率随正向电场增加而增大，随反向电场增加而减小，红外谱强度均随电场的增大而逐渐减小．由基态到第1-10激发态的波长增大，激发能减小．

英文摘要：

The geometrical structures and excited state properties of AgBr under an electric field are studied by using B3P86 method. The electric field effects on the bond length, total energy, energy level, harmonic frequency, infrared intensity and the excited state properties of AgBr are discussed. The results show that with the increase of the external electric field, the bond lengths, dipole moments, energy gaps and Fermi levels decrease, while the total energies increase. The harmonic frequencies increase, whereas the infrared intensities decrease under an electric field. The wavelengths from the ground state to the first ten excited state are found to increase, however, the excited energies decrease with the increase of the external electric field.